Wearable absorbent articles (e.g., taped diapers, pull-on diapers, training pants, sanitary napkins, panty liners, incontinence briefs, and bandages) typically offer the benefit of receiving and containing the bodily exudates of a wearer. Disposable varieties of such absorbent articles are commonly known, and are typically mass produced on a high speed production line. Some disposable absorbent articles include a mechanical fastening system (e.g., hook/loop or tab/slot) for maintaining the article in a desired position or configuration prior to, during, and/or after use of the article. Such fastening systems may include one or more elements that extend laterally outwardly beyond the side edges of the article, such as commonly known fastening tabs. These laterally outwardly extending portions of the fastening system may increase the risk of contamination or damage to the article, an article element, and/or the manufacturing equipment during a high speed manufacturing process. Repositioning the outwardly extending portions of the fastening system (e.g., by folding the portion laterally inward) may reduce the likelihood of damage or contamination, but the folded fastening system element may not remain suitably folded for a desired amount of time (e.g., the duration of the manufacturing process) due to the high speed nature of the manufacturing process.
A fastening system that includes a mechanical fastener having commonly known hooks or other similar features may be maintained in a folded configuration by engaging the mechanical fastener with a complementary element of the fastening system, such as loops or a nonwoven portion. Such mechanical fastening systems are generally engaged by entangling the hooks or other similar feature with the complementary element. However, an engaged mechanical fastening system still may not provide sufficient bonding strength to maintain the fastening system in the desired folded configuration during a high speed manufacturing process. Therefore, in order to increase the bond strength of the mechanical fastener, a bonding agent such as an adhesive may be applied to one or more portions of the mechanical fastener prior to folding and/or engaging the fastening system. Conventional adhesives such as commonly known pressure sensitive adhesives generally form permanent bonds. The bond strength provided by at least some permanent bonding agents such as commonly known hot-melt adhesives typically remain substantially constant or may even increase between the time the absorbent article is made and the time it is purchased and/or used by a consumer. For example, during shipping and/or storage of disposable absorbent articles, the articles may be subjected to a wide variety of temperature and/or humidity conditions. Periods of increased temperature (e.g., 50° C. or more) may cause conventional hot-melt adhesives to exhibit an undesirable increase in bond strength when the article is to be used by a consumer. It is believed, without being limited by theory, that at higher temperatures the flowability of the hot-melt adhesive increases enough for it to penetrate further into the pores or capillaries of the substrate. Then, when the adhesive cools, it requires more force to separate the joined surfaces.
While permanent bonds may provide the desired bond strength during a high speed manufacturing process, the increased bond strength and/or infrangibility of the adhesive may be undesirable at other times such as when a consumer attempts to use the article or fastening system and it becomes necessary to break the bond. In order for a disposable absorbent article to be used as intended by a consumer, it may be necessary or desirable to unfold or reposition the fastening system or other portion of the article. The increased bond strength and/or infrangible bond provided by a permanent bonding agent may result in an undesirably difficult unfolding or repositioning experience. In addition, mechanical fastening systems are typically configured to be refastenable (i.e., the fastener can be fastened and unfastened more than once without substantial loss of fastening capability). Applying a permanent bonding agent to the mechanical fastener may undesirably reduce the refastenability of the mechanical fastener, for example, by covering up the engageable portions of the mechanical fastener.
One way to address the high bond strength problems described above may be to use a temporary bonding agent such as a temporary strength adhesive to maintain the fastening system in a folded configuration. Temporary strength adhesives, sometimes referred to as “fugitive” adhesives, are known (see, e.g., U.S. Publication No. 2006/0027320, filed by Kueppers, et al., on Jun. 20, 2005). However, fugitive adhesives are typically used to create temporary, frangible paper-to-paper bonds, for example, for joining cardboard containers and/or portions thereof to one another or for use with envelopes, labels, and the like. Typically, when the bond provided by a fugitive adhesive is broken, the adhesive is no longer tacky and does not readily adhere to anything. Fugitive adhesives are not known in the art for use in the fastening system of an absorbent article such as a disposable diaper. One reason for this may be the difference in materials used in absorbent articles (which typically include at least some polymeric materials as opposed to only paper). Another reason may be that the fastening system for an absorbent article is generally intended to provide a permanent bond or, in the case of a refastenable fastening system, a quasi-permanent bond to maintain the article in the desired position and/or configuration on a wearer. In other words, one goal of the fastening system is to provide sufficient bond strength to prevent the article from undesirably coming unfastened during the intended use of the article, and a temporary bonding agent will typically not help achieve this goal.
In addition, known fugitive adhesives may not form a strong enough initial bond to make them capable of temporarily holding folded portions of absorbent articles in place during a high speed manufacturing process where the folded portions of the absorbent articles could come in to contact with other objects in the manufacturing process. Water-based fugitive adhesives, which are typically used in labeling and envelope applications, have relatively low bond strengths when wet (i.e., when applied). This may be sufficient for use in bonding paper to paper, but it is generally not sufficient for the absorbent article applications described herein. Further, in order for conventional fugitive adhesives to lose strength, they may require active heating, radiation, or the like to reduce their strength, all of which are impractical for use with absorbent articles. Other known fugitive adhesives are solvent cross-linked materials, which may not be suitable for use in the absorbent articles described herein.
Accordingly, it would be desirable to provide a disposable absorbent article comprising a frangible bonding agent for maintaining the article in a particular configuration during a high speed manufacturing process. It would also be desirable to provide a fastening system that is relatively easy to open by a consumer. It would further be desirable to provide a fastening system comprising a frangible bonding agent, which does not impair the fastenability or refastenability of a fastening system.